Allow configutation of the H5 back trace management from the environment (see gh-120)
Allow configutation of the H5 back trace management from the environment (see gh-120)

andreabedini/PyTables,jennolsen84/PyTables,cpcloud/PyTables,jennolsen84/PyTables,rabernat/PyTables,mohamed-ali/PyTables,tp199911/PyTables,jack-pappas/PyTables,FrancescAlted/PyTables,tp199911/PyTables,gdementen/PyTables,dotsdl/PyTables,avalentino/PyTables,joonro/PyTables,PyTables/PyTables,joonro/PyTables,gdementen/PyTables,joonro/PyTables,cpcloud/PyTables,mohamed-ali/PyTables,cpcloud/PyTables,avalentino/PyTables,rabernat/PyTables,dotsdl/PyTables,rdhyee/PyTables,FrancescAlted/PyTables,joonro/PyTables,cpcloud/PyTables,FrancescAlted/PyTables,tp199911/PyTables,gdementen/PyTables,dotsdl/PyTables,jennolsen84/PyTables,jack-pappas/PyTables,jack-pappas/PyTables,jennolsen84/PyTables,PyTables/PyTables,rabernat/PyTables,avalentino/PyTables,mohamed-ali/PyTables,jack-pappas/PyTables,rdhyee/PyTables,andreabedini/PyTables,rdhyee/PyTables,gdementen/PyTables,PyTables/PyTables,dotsdl/PyTables,rdhyee/PyTables,jack-pappas/PyTables,andreabedini/PyTables,mohamed-ali/PyTables,andreabedini/PyTables,tp199911/PyTables,rabernat/PyTables